ORLANDO, Fla. President Barack Obama on Thursday met survivors of a massacre at an Orlando gay nightclub and relatives of the 49 people killed and said the United States must act to control gun violence and fight what he called homegrown terrorism.

"The last two terrorist attacks on our soil - Orlando and San Bernardino - were homegrown," Obama told reporters, before urging Congress to pass measures to make it harder to legally acquire high-powered weapons like the assault rifle used in the attack on Sunday.

"I'm pleased to hear that the Senate will hold votes on preventing individuals with possible terrorist ties from buying guns," he said.

Obama and Vice President Joe Biden arrived in Orlando, Florida, four days after a U.S.-born gunman claiming allegiance to various Islamist militant groups carried out the deadliest mass shooting in modern U.S. history.

New details emerged on Thursday about the gunman's activity on Facebook and text messages he sent during the shooting rampage.

Obama said he "held and hugged" grieving family members before laying flowers at a memorial for the victims of the attack on the Pulse nightclub. Police killed the gunman, Omar Mateen, 29, a U.S. citizen born in New York to Afghan immigrants.

Islamic State claimed responsibility for the attack but U.S. officials have said they do not believe Mateen was assisted from abroad. CIA Director John Brennan told a Senate Intelligence Committee hearing on Thursday that the agency had "not been able to uncover any direct link" between Mateen and militants abroad.

A married couple also claiming allegiance to Islamic State shot dead 14 people in San Bernardino, California, in December.

ORLANDO MOURNS

Orlando mourned the dead after what was also the worst attack in America on the lesbian, gay, bisexual and transgender community. Wakes were under way for at least three victims - Kimberly Morris, Anthony Luis Laureano Disla and Roy Fernandez.

Twenty-three of the 53 wounded remained hospitalized, six in critical condition, according to the Orlando Regional Medical Center.

During his attack, Mateen posted messages on Facebook and called a news station.

One Facebook message, apparently referring to air strikes against Islamic State by the United States and its allies, said: "You kill innocent women and children by doing us air strikes ... now taste the Islamic State vengeance," according to U.S. Senate Homeland Security Committee Chairman Ron Johnson, who asked Facebook to turn over material from Mateen's accounts.

Also during the three hours he was holed up in a bathroom inside the nightclub, Mateen exchanged text messages with his wife, Noor Salman, CNN reported, citing a law enforcement official it did not identify. Salman is under investigation to find out whether she knew about Mateen's plans ahead of time.

Local news website TCPalm reported that Mateen, who worked as a security guard, was frequently suspended while he was in junior high and high school, and was passed to the next grade despite poor academic performance, citing records from St. Lucie County schools.

CONGRESS UNDER PRESSURE

The attack sparked a new debate over how the United States responds to Islamist militant violence at home and abroad, with Republican Senator John McCain telling reporters on Thursday he viewed Obama as "directly responsible" for the Orlando attack because of his failure to prevent the rise of Islamic State.

Shortly afterward, McCain said on his official Twitter feed that he was referring to Obama's national security decisions, "not to the President himself."

Mateen carried out the slaughter with an assault weapon and handgun that had been legally purchased although he had twice been investigated by the FBI for possible connections with militant Islamist groups.

Obama reiterated his frustration over the failure of Congress to pass any gun control measures in more than two decades. The massacre put pressure on Congress to act.

After a marathon of speeches by Democrats on Wednesday and into the early hours of Thursday, a Democratic senator said Republicans had agreed to hold votes on measures to expand background checks and prevent people on U.S. terrorism watch lists from buying guns.

No formal deal between the parties for votes was announced, and it was unclear when and how the Senate would proceed with the votes, which would be amendments to an appropriations bill funding the Commerce and Justice departments. Even if votes are scheduled, it is unclear whether any of the bills can gain enough support to pass the Senate.

Senator John Cornyn of Texas, the No. 2 Republican in the Senate, said the chamber would most likely vote on four gun control measures on Monday.

Republicans, who currently hold a 54-person majority in the 100-seat Senate, have blocked a number of Democratic-backed gun control measures over the years, saying they infringe on Americans' constitutional right to bear arms.

Presumptive Republican presidential nominee Donald Trump also joined the gun debate, announcing on Wednesday he would meet with the National Rifle Association to talk about barring people who are on terrorism watch lists from buying guns.

(Additional reporting by Julia Harte and Peter Eisler in Orlando, Patricia Zengerle and Jonathan Landay in Washington and Zachary Fagenson in West Palm Beach, Florida; Writing by Scott Malone; Editing by Howard Goller and Peter Cooney)

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